1. Field of the Invention
The present invention relates to improvements in a railroad spike forging machine, and particularly in the apparatus for forming the head on the railroad spike, and also ejecting the finished spike from the die.
2. Brief Description of the Prior Art
Manufacture of railroad spikes by forging steel stock is well known. Two primary types of railroad spike forging machines have long been used in this country. The first is known as a Barr spike machine, and a second type was manufactured by Youngstown Machine and Foundry Co. The present invention incorporates certain concepts from both the Barr and Youngstown machines, with respect to drive and supply of a square steel bar as raw material to a head forging location, while significantly modifying prior art techniques to insure an accurately formed spike at production rates previously considered impossible.
A Barr-type machine is illustrated, for example, by Barr, U.S. Pat. No. 1,025,670. A spike forging sequence on a Barr machine briefly will be described. Square steel bar sized 5/8 inches (for 6 inch spikes) or 9/16 inches (for 51/2 inch spikes), in stock lengths typically 30 to 40 feet progressively is heated to a forging temperature by being passed through an induction heater, for example. The heated bar is indexed through a set of rotating pointer rolls, where a spike blank simultaneously is pointed and cut to a length adequate to enable a head to be formed and result in a spike of the proper length. A hot, pointed spike then is engaged by a set of powered feed rollers which accelerates the pointed blank longitudinally to a die area, where a mechanism momentarily stops the pointed blank at a leading edge position for forging the head. A gripper die engages the shank of the spike from above as a header die impacts onto the leading edge of the blank and forms the spike head. As the header and gripper mechanism move away from the formed spike, a bottom kicker device is actuated to elevate the leading edge of the spike upwardly out of the die, and hopefully into a position where a side kicker mechanism may push or reject the spike sideways, and out of the main die. Ideally, this sequence was accomplished rapidly, but in an indexing fashion, and with inherent problems. The main die and kicking arrangement could not react when a spike blank did not fully enter the main die, since the bottom kick would not sufficiently elevate the spike for the side kick mechanism to transversely remove the spike. Accordingly, the next blank indexed longitudinally from the accelerating rollers would over climb the misejected spike, and jam the machine. The circumstance of a spike blank not reaching an appropriate position in the die cavity so as to be raised properly by the bottom kick for a side wipe is referred to in the art as a "cobble".
Known machines and methods for making spikes are illustrated by the prior U.S. Patents, as follows:
______________________________________ IRWIN 685,477 BARR 1,025,670 STETTER 1,070,744 BERKLEY 1,582,895 CRANE 1,774,915 FRIEDMAN 2,023,636 VAN DE MEERENDONK 3,299,451 ______________________________________
In addition to the above-listed prior art, FIGS. 1-3 of the present invention illustrate a recent design for a machine of the category upon which improvement is predicated herein, as designed for applicant's assignee by Wean United, Inc., Pittsburgh, Pa. The device illustrated in FIGS. 1-3 represents one starting point for understanding the present invention herein, in that this device could not achieve the results achieved after the specific improvements and modifications, which hereafter are particularly pointed out, were included. The prior art patents, as well as certain prior approaches illustrated at FIGS. 1-3, commonly evidence mechanical interconnections for cams and actuators, which have proven incapable of the exact timing of interrelationships required for the manufacturing speeds achieved herein. The present invention achieves tremendously increased production speeds by a theory of operation wherein a square steel rod continously is pointed and then accelerated into a main die cavity, and ejected before a subsequent blank arrives. In other words, the present invention is predicated upon a high-speed continuous throughput of pointed blanks to a downstream head forging location with a blank acceleration of sufficient speed into the main die to allow forging and ejection before a cobble of later blanks. To achieve this object, the present invention uses a stationary novel cooperation between bottom and side-kicking members which ensure a positive clearing of the die.
In contrast, the IRWIN patent teaches a spike making machine wherein a moving die is employed for an intermittent heading operation. Similarly, STETTER illustrates an approach to spike making wherein feed fingers pick-up a spike blank and position the blank between two movable die sections. BERKLEY illustrates an automatic pointing machine wherein electronics control an hydraulically actuated nipper arrangement, with a blank carried forward from feed roll to a heading position and dropped into a die channel, by the nippers.
CRANE illustrates a spike making machine wherein separate confining dyes and pointing dyes are employed to forge a spike, as shown more particularly at FIGS. 8-15. VAN DE MEERENDONK illustrates an upsetting head and an ejecting pin which cooperates with various movable parts required to eject the length, as shown in FIG. 2.
The present invention maintains a stationary die, while insuring ejection of the blank through a novel bottom kick and side wiping arrangement, which cooperates with a novel die construction. As previously discussed, the sequence of steps herein for forming a spike begins with pointing a blank, through pointer rollers which substantially function as the pointer rolls in the prior art spiking machine taught by FRIEDMAN. However, unlike FRIEDMAN, the present invention does not require moving main die sections, nor are the pointer rollers intermittently operated, as by a pawl and ratchet arrangement. Rather, the pointer rollers herein form spike blanks continuously, with an accelerating roller set accepting a pointed blank and accelerating it sufficiently to provide time for head forging and ejecting steps, before a following blank is accelerated into the die station.
A first object of the present invention is to provide a main die mechanism which will support the spike blank so that cobbling is greatly reduced, while also allowing increased rates of speed for spike production. A second object of the present invention is to configure a die ejecting mechanism which will enable a continuous throughput of steel blanks into the main die region, through accurate timing between pointing and forging steps. A synergistic cooperation between a continuous pointer roller motion and the accelerating roller mechanism is a necessary predicate to achieving both objects.